Two independent methods of forecasting based on judgment and experience have been prepared each month for the past $10$ months. The forecasts and actual sales are as follows:

a$.$ Compute the MSE and MAD for each forecast.

Note: Round your answers to $\backslash (\backslash$mathbf$\{2\}\backslash )$ decimal places.

Answer is complete but not entirely correct.

c$.$ Prepare a naive forecast for periods $2$ through $11$ using the given sales data. Compute each of the following;

MSE,

MAD,

Tracking signal at month $10,$ and

$2$s control limits$.$

Note: Negative values should be indicated by a minus sign. Round your answers to $2$ decimal places.

Answer is complete but not entirely correct. $($solve for incorrect ones$)$